Optical fiber cables are manufactured containing a large number of individual fibers, either in the form of ribbons containing, for example, twelve fibers in a parallel array, with several ribbons then being stacked together within the cable jacket, or in the form of loose fibers bundled within the fiber jacket along with one or more strength members. It is the practice in either case, as well as in other cable configurations, to color code the fibers for identification purposes. Thus, in the manufacture of the individual fibers, each fiber is given a protective coating of an ultraviolet (UV) curable aciylate, over which is applied a UV curable ink coating generally of approximately 6 to 9 microns thick of the desired color. It is also generally the practice that the various colored inks contain titanium dioxide (TiO.sub.2), which enhances and brightens the color for enabling the different colors to be more quickly and efficiently distinguishable.
The individual fibers are drawn and wound upon reels containing, for example, several kilometers of the fiber having a specific color. For greater continuous lengths of fiber, it is necessary to splice the trailing end of a first colored fiber to the leading end of a second fiber of the same color. However, in order to achieve an optimum splice, it is necessary to prepare the mating ends of the two fibers by removing the ink coating and the protective coating so that such a splice may be effected. Removal of the coatings has, heretofore, been accomplished by insertion of the fiber end in a bath of concentrated sulfuric acid, at full strength, designated as 36N, at approximately one hundred and ninety degrees (190.degree. C.), plus or minus five degrees (.+-.5.degree. C.). Where the fiber has no colored ink coating, this process makes possible high strength (&gt;200-235 kpsi, where kpsi is kilopounds per square inch) splices. On the other hand, this process does not produce fiber ends of sufficient lack of contamination by the coatings to achieve the required splice strength, especially where the ink coating is a UV curable ink containing titanium dioxide. It is believed that this results from the fact that the titanium dioxide does not completely dissolve in the sulfuric acid and, as a consequence, contaminates the bath. Thus, when the fiber is placed in the bath and its coatings are dissolved, the titanium dioxide in the bath redeposits on the bare glass fiber and damages it to the extent that its tensile strength is weakened, thereby weakening the subsequent splice. On terrestrial systems, weakened splices are easily detected and accessed. However, submarine cables, as can well be appreciated, present a far more formidable problem. Weak splices in a submarine cable are anathema, and, as a consequence, it is necessary to use expensive coloring inks which must be especially designed for the submarine cable use.
What is needed, and, apparently, has not heretofore been used, is a method or process for removing the coatings of an optical fiber, one of which is a UV curable colored ink containing an enhancing agent such as titanium dioxide, without contaminating or damaging the fiber from which the coatings are removed.